Endoscopes are generally used to examine various biological cavities, such as those in the alimentary canal or the bladder. Such may be biological cavities of a human or otherwise. A physician typically has a limited view of the interior of the cavity in which the distal end of the endoscope is located, due to the fact that tube like organs, such as the esophagus, intestine, and bladder, may be relatively soft and pliable such that the organ collapses about the endoscope. In order to have a better view of the cavity, air or liquid (such as water) may be traditionally forced into the cavity causing the cavity to temporarily expand.
Devices have generally been developed to distend tube-like organs with hardened or scarred tissue. One such device used by physicians is the balloon catheter. In the cardiovascular system, balloon catheters are used to open blocked or significantly narrowed arteries. In the gastrointestinal system, a modified balloon catheter, or balloon dilator, may be used to exert a radial force on the surrounding walls of tube-like organs, for the purpose of dilating strictures. Balloon dilators are commonly used in the gastrointestinal tract for strictures of the esophagus, pylorus, duodenum, sphincter of odi, biliary tree and colon.
Balloon catheters and dilators have also been used for expansion without the exertion of large radial forces. These balloon dilators are instead used to hold an organ open for an extended period of time, usually for a treatment of some kind. This treatment may include delivering medicaments to a specific site within the cardiovascular system, or the activation of a photosensitizing agent in a variety of organs, for example.
Devices have also been proposed to expand non-tubular organs in order to create a uniform surface for the activation of a photosensitizing agent. Such organs include the uterus and the bladder, for example.
Regardless, such distending devices may conventionally be positioned with respect to a target tissue with the aid of guidewires, or specialized introducers, being passed through the lumen of an endoscope, or by being passed “blindly” through connecting body lumens. However, there is typically no direct viewing of the positioning procedure or the target tissue. Therefore, difficulties exist in remotely and effectively treating a disease or ailment. Further, using guidewires typically requires, multiple insertions into the cavity to perform a treatment. Generally, the more insertions required, the greater the chance for damage to surrounding tissue. For example, in a typical guidewire related gastrointestinal PDT procedure, a physician typically first inserts an endoscope to determine the treatment site. Once the site is located, a guidewire is typically inserted into the instrument channel of the endoscope. The endoscope is then withdrawn and the guidewire is left behind at the treatment site. Next, a balloon dilator is typically inserted using the guidewire as a central axis. To view the site, the endoscope is then reinserted alongside the dilator. When the procedure is complete, all devices are removed from the site.
In situations where devices are passed either through an endoscope or are passed “blindly”, there is a risk that the device may not be properly positioned at the target tissue, or more significantly, pass into unintended tissue and/or lumens causing harm to the patient. It is generally desirable to mitigate this risk. Further, it is generally desirable to minimize the number of insertions that must be performed to treat an area of interest.